Antimicrobial-resistant microbial infections are associated with poor clinical outcomes including increased morbidity, mortality, and healthcare costs among infected patients. The prevalence of these organisms in such facilities in the United States has steadily increased over the last 30 years. Phenotypic antimicrobial susceptibility testing (AST) of microorganisms is critical for informing physicians of appropriate therapeutic regimens. Using current methods, AST determination typically requires a minimum of eight hours, rendering it an overnight process due to shift work in many clinical microbiology laboratories. While awaiting a determination from current AST methods, patients are often administered broad-spectrum antimicrobials which often have significant detrimental effects on patient health and/or contribute to the growing antimicrobial resistance epidemic. Furthermore, this time delay to getting accurate antimicrobial treatment information increases patient stays in hospitals, thereby increasing costs and inconvenience to the patient.
Accordingly, a need exists for a method that rapidly determines antimicrobial susceptibility of a microbial infection. The method described here is further advantageous in that it addresses this need in a cost-effective manner because it is compatible with existing assay hardware components.